1. Field of the Invention
The present invention relates, in general, to variable capacity rotary compressors and, more particularly, to a variable capacity rotary compressor which has a pressure controller to allow an internal pressure of a compression chamber where an idle operation is executed, to be equal to an internal pressure of a hermetic casing.
2. Description of the Related Art
Recently, a variable capacity compressor has been increasingly used in refrigeration systems, such as air conditioners or refrigerators, to vary the cooling capacity as desired, to accomplish an optimum cooling operation and saving energy.
In Korea Patent Application No. 2002-61462 there is disclosed a variable capacity rotary compressor which was filed by the inventor of the present invention. In the Korea Patent Application No. 2002-61462, the compressor is designed to execute a compression operation in either of two compression chambers having different capacities.
The variable capacity rotary compressor includes two compression chambers and two eccentric units. The two eccentric units are respectively installed in each of the compression chambers, and are operated so that one of two rollers respectively placed in each of the compression chambers, is eccentric from a rotating shaft to execute a compression operation while a remaining one of the rollers is released from eccentricity from the rotating shaft to prevent the compression operation from being executed, according to a rotating direction of the rotating shaft. Each of the eccentric units includes an eccentric cam and an eccentric bush. The eccentric cams of the eccentric units are respectively provided on an outer surface of the rotating shaft to be placed in each of the compression chambers. The eccentric bushes are rotatably fitted over the eccentric cams, respectively. Further, the rollers are respectively fitted over each of the eccentric bushes. A locking pin causes one of the eccentric bushes to be eccentric from the rotating shaft while causing a remaining one of the eccentric bushes to be released from eccentricity from the rotating shaft, when the rotating shaft rotates. Two vanes are respectively installed in each of the compression chambers to reciprocate in a radial direction. The compression chambers are respectively partitioned into an intake space and a discharging space by each of the vanes.
The variable capacity rotary compressor is constructed such that the compression operation is executed in one of the two compression chambers having different capacities while the idle operation is executed in a remaining one of the compression chambers, by the eccentric units. Thus, the compression capacity of the compressor is varied by only changing the rotating direction of the rotating shaft.